• A marketing company performed a thorough test of the four main virtual assistants.
  • The results paint a clear picture that the Google Assistant smartphone app is the most efficient virtual assistant.
  • Cortana is in second place, Amazon’s Alexa is in third, and Apple’s Siri came in last.


A new report from marketing agency Stone Temple Consulting confirms what we knew already: Google Assistant is the most efficient virtual assistant as compared to its top rivals. Apple’s Siri came out last for efficiency in the same set of tests.

Stone Temple Consulting pit the top four virtual assistants against each other to measure out two metrics: how many questions will the virtual assistants answer, and how many of those questions will they answer fully and correctly? The Google Assistant smartphone app topped Amazon’s Alexa, Microsoft’s Cortana, and Apple’s Siri in both metrics.

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Interestingly, testers performed the experiment on both the Google Assistant smartphone app and on a Google Home device, resulting in two different sets of stats. The report does not make it clear which devices were used in the experiment, but the writer of the report mentions owning a Google Pixel 2, an iPhone, and multiple Google Home and Amazon Echo devices. So we can assume Google Assistant was queried on the Pixel 2.

Here is the chart representing the results of the experiment:

efficient virtual assistant Stone Temple Consulting

As you can see, for some reason the Google Assistant smartphone app does better than the Google Home. However, both versions of Google Assistant top all other assistants in both categories, with the notable exception of Cortana answering questions more fully and correctly than the Google Home device.

From the results, we can draw these conclusions:

  • The Google Assistant smartphone app answers more questions and gets more answers right than any other virtual assistant in its class.
  • Microsoft’s Cortana is comfortably in second place with both sets of results not too far off from Google’s.
  • Amazon Alexa does a pretty good job of answering questions correctly but is lacking when it comes to attempting answers.
  • Apple’s Siri is way behind when it comes to attempting answers, but doing OK when it comes to answering questions correctly.

To perform the experiment, testers delivered a total of 24,710 queries, which is an incredibly large sample size.

Another interesting graph supplied by Stone Temple Consulting gives us the number of incorrect responses provided by the assistants in this report and compares it to the similar report it ran last year. Check it out:

efficient virtual assistant Stone Temple Consulting

As you can see, Siri actually did a little worse this year than last, and Alexa did a lot worse. Amongst all four assistants, Cortana has the lowest rate of incorrect responses two years running, besting both versions of Google Assistant.

You can read the full report from Stone Temple Consulting at its website.

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